The present invention generally relates to adding assisting force for the tilting a cab for power machines for access to components under the cab. In particular, the present invention relates to a multiple spring system assisting in the tilting of a rear pivoting cab on a power machine.
Power machines, such as skid steer loaders, often have a cab which covers an operator compartment. Many times this cab is a rear pivoting cab which gives the access to components requiring service under the operator compartment. Rear pivoting cabs, because of the materials used, are often heavy and the pivot position results in a large moment being generated when the cab is in closed position.
To assist the operator in opening and closing the cab rear pivoting cabs use a pair of gas springs one on each side of the cab to reduce the manual force required to tilt the cab. It has been undesirable to merely use larger or stronger springs to assist in opening the cab, because of size limitations on the sides of the cab, and importantly as the cab tilts, the center of gravity of the weight actually goes over center. That is, the center of gravity of the cab moves behind a vertical plane passing through the axis of pivot or rotation. The additional force of a large spring then exerts a high force which holds the cab tilted up with a large force and the operator must counter the spring force to initiate returning the cab to its usable position.
The gas springs usually are mounted close to the pivot of the cab to reduce the length of the spring when gas springs are too long, they are unstable.